首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   688884篇
  免费   12360篇
  国内免费   5489篇
化学   382222篇
晶体学   9857篇
力学   30068篇
综合类   263篇
数学   83011篇
物理学   201312篇
  2021年   4970篇
  2020年   5762篇
  2019年   5972篇
  2018年   6691篇
  2017年   6730篇
  2016年   11055篇
  2015年   8419篇
  2014年   11428篇
  2013年   30982篇
  2012年   24531篇
  2011年   29883篇
  2010年   19965篇
  2009年   19949篇
  2008年   27539篇
  2007年   27738篇
  2006年   26506篇
  2005年   23988篇
  2004年   21486篇
  2003年   19155篇
  2002年   18836篇
  2001年   20777篇
  2000年   16132篇
  1999年   12705篇
  1998年   10079篇
  1997年   10047篇
  1996年   10122篇
  1995年   9075篇
  1994年   8784篇
  1993年   8307篇
  1992年   9364篇
  1991年   9353篇
  1990年   8722篇
  1989年   8486篇
  1988年   8592篇
  1987年   8261篇
  1986年   7924篇
  1985年   10954篇
  1984年   11040篇
  1983年   9111篇
  1982年   9755篇
  1981年   9321篇
  1980年   8976篇
  1979年   9408篇
  1978年   9695篇
  1977年   9705篇
  1976年   9584篇
  1975年   9106篇
  1974年   9037篇
  1973年   9242篇
  1972年   6182篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
41.
Journal of Radioanalytical and Nuclear Chemistry - In this paper a study for the selection of an NPE (nonylphenol ethoxylates)—free cocktail is discussed in order to be used for our routine...  相似文献   
42.
Radiophysics and Quantum Electronics - A well-known simplified model of turbulent convection from local sources of buoyancy and/or momentum acting for a short time has been developed and...  相似文献   
43.
44.
Astrelin  V. T. 《Russian Physics Journal》2021,63(10):1728-1734
Russian Physics Journal - A solution for the one-dimensional Poisson problem for a layer on the surface of a plasma ion emitter is obtained. The case of plasma with a directed ion velocity greater...  相似文献   
45.
Fomenko  T. N. 《Mathematical Notes》2021,110(3-4):583-591
Mathematical Notes - The notion of a $$\lambda$$ -generalized-search multivalued functional on an $$f$$ -quasimetric space is introduced. An existence theorem for zeros of such functionals is...  相似文献   
46.
Ukrainian Mathematical Journal - We establish new criteria of compatibility for a linear system of equations (equivalent to the Kronecker–Capelli theorem) or inequalities (equivalent to the...  相似文献   
47.
Chen  R. J.  Chen  W.  Kong  F. L. 《Analysis Mathematica》2022,48(1):19-28

Restricted testing conditions were considered recently. For the maximal operator, Hytönen, Li and Sawyer [8] first obtained parental testing condition. Later, they [9] showed that it suffices to restrict testing to doubling cubes. Chen and Lacey [3] gave a similar restricted testing condition. In our paper, we discuss a version of the latter in the multilinear setting.

  相似文献   
48.
Physics of the Solid State - The external factors which influence the ferromagnetic resonance (FMR) line width in bilayer (ferromagnet/antiferromagnet) exchange-biased systems are studied. The...  相似文献   
49.
A temperature control unit was implemented to vary the temperature of samples studied on a commercial Mobile Universal Surface Explorer nuclear magnetic resonance (MOUSE-NMR) apparatus. The device was miniaturized to fit the maximum MOUSE sampling depth (25 mm). It was constituted by a sample holder sandwiched between two heat exchangers placed below and above the sample. Air was chosen as the fluid to control the temperature at the bottom of the sample, at the interface between the NMR probe and the sample holder, in order to gain space. The upper surface of the sample was regulated by the circulation of water inside a second heat exchanger placed above the sample holder. The feasibility of using such a device was demonstrated first on pure water and then on several samples of bread dough with different water contents. For this, T1 relaxation times were measured at various temperatures and depths and were then compared with those acquired with a conventional compact closed-magnet spectrometer. Discussion of results was based on biochemical transformations in bread dough (starch gelatinization and gluten heat denaturation). It was demonstrated that, within a certain water level range, and because of the low magnetic field strength of the MOUSE, a linear relationship could be established between T1 relaxation times and the local temperature in the dough sample.  相似文献   
50.
Crystallography Reports - The orientation of grains and the special boundaries formed by them in multicrystalline silicon has been studied by electron backscattered diffraction. It is found that...  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号